Vibrating contact regulator



Jan. 22, 1929.

VIBRATING CONTACT REGULATOR Filed Dec. 19, 1927 Fig.4.

Fig 2.

Patented Jan. 22, 1929.

UNITED STATES PATENT OFFICE.

FRANQOIS MAURON, OF BADEN, SWITZERLAND, ASSIGNOR TO AKTIENGESEILSCHAFT BROWN, BOVERI AND GIIEL, OF BADEN, SWITZERLAND.

VIBRATING CONTACT REGULATOR.

Application filed December 19, 1927, Serial No. 241,219, and in Germany August 30, 1926.

This invention relates to automatic voltage or other regulators designed to operate on the shunt circuits of dynamos and alternators and is particularly concerned with regulators of the vibrating contact type'in which a resistance in the field of thegenerator or exciter is periodically short-circuited.

The main object of the invention is the provision of a voltage or other regulator. of the above type capable of dealing with comparativelylarge field currents and at the same time giving very close regulation.

A further object of the invention is the provision of a regulator of the type described in which a high degree of precision in operation is combined with simple construction. Other and further objects will be pointed out or indicated hereinafter or will be apparent to one skilled in the art upon an understanding of the invention or its employ ment in practice.

In the drawingaccompanying this specification are shown two different arrangements in which the invention may be embodied, but it is to be understood that these are presented for purpose of illustration only and are not to be accorded any interpretation having the effect. of limiting the claims short of the true and most comprehensive scope of the invent-ionin the art.

In the drawing:

Figure 1 is a diagrammatic view of voltage regulating apparatus for a self-excited shunt-wound direct-current dynamo.

Figure 2 is a diagrammatic view of a similar apparatus applied to the voltage regulation of an alternator.

Automatic voltage regulators of the vibrating contact type as hitherto known in the art may be divided into two classes, one in which a single resistance is periodically cut in and out of circuit and the other in which I he prmfided with special damping arrange ments if satisfactory operation is to be secured.

The present invention provides a voltage regulating apparatus which does not suffer from the disadvantages enumerated for the two types above, while at the same time retaining the good points of both. This is attained by a combination of main and auxiliary contacts cooperating in sliding or like relationship with the regulating resistance, the two contacts being separated by a small number of resistance steps and coupled together. The main contact gives coarse regulation and the auxiliary contact in conjunction with a trembler relay provides the fine regulation required. The arrangement is such that in addition to the section of resistance which is permanently bridged by the main contact there is a further section which is intermittently short-circuited, this second resistance section lying between the main and auxiliary contacts and bearing a suitable relation to the total resistance of the exciter field circuit. This results in uniform loading of the vibrating contacts throughout the whole range of regulation.

An understanding of the invention will be most readily obtained from a consideration of the examples illustrated in the drawing accompanying this specification.

In Figure 1 of the drawing the reference character 1 denotes the armature and 2 the field of a dynamo, the field 2 being connected in shunt to the armature through the regulating resistance 3. The latter is provided with contacts 4 and 5 which are arranged in sliding or other variable relationship to the resistance. These movable contacts are attached to the core 6 which is surrounded by windings 7 and 8, the former of which is connected in parallel with the armature of the dynamo, while the latter is connected across the contacts 10 and 11 of the trembler relay. The trembler contact 11 is attached to the moving armature 14 and is attracted by the relay core 9 against the action of the spring 15. The core 9 is provided with two windings of which one (12) is connected to the terminals of the dynamo 1 and the other (113) to the contacts 10 and 11 of the trembler re ay.

The 0 eration of the regulator is as followsz hen the E. M. developed by the dynamo 1 is zero there will be no current flowing in the coils 7, 8 and 12. The upper portion ofthe regulating resistance 3 is shortcircuited by the contact t and the lower portion which lies between the contacts 4 and 5 'is likewise .short-circuitedby the contacts .10

and 11 of the trembler relay which. are held together by the spring 15. The contacts 4 and 5 will take up their lowest position owing to the weight of the core 6 to which they are attached As soon, however, as the volt- .age at the terminals ct the dynamo 1 reaches its prescribed value, the pull of the magnet 9 exactly balancesthat of the spring 15, al-

though the contacts still remain closed. If the. voltage of the dynamo exceeds: the prescribedvalue by a small amount, the electro tive resistance bedenotecl by R. Then by varying. the ratio.

magnetic pull exerted by the coil 12 will over- .come the pull of the-spring15 andthe contacts 10and 1 1 will be scparatedwith the resultfthat the section of resistance lying between contacts 4;. and 5 is inserted in the dynamo field circuit. Simultaneouslywith the .openingof the trembler relay contacts 10 and 11 the voltage of the dynamo will drop to below the normal andthe spring 15. being now able .to overcome the pull of the magnet 9. will 1 cause. the. contacts to close. the-dynamo will thereuponriseoncemore and the sequence of operations described ,above will be repeated; the openingand closing .ofthe contacts 10 and ll taking place so The voltage of rapidly that-thearmature 14 is given a trembling motion. The section :ofQresistance lying between the contact-s t and 5 is thus alternately cut into the field circuit and short-circuited. Let the resistance of this section be r the time during which itisin circuit with the field 2 be 2,. and the: time duringwhich. it is short-circuited be t2.v- The same effect may be considered. as beingproducedby a resistance of, appropriate size permanently connected in circuit this, resistance representing the efiectivevalue of theresistanoe between the contactsaand 5. Let. this efiec t 2 "duration of short-circuit z duration of break thevalue of. the-efl'ective resistance R is also varied. Thus it a change int-he trembling 1110131011 of the contact 11 causesan ncrease 1n the effective-res1stance,.the current in the field:

circuit-will be reduced although'not in. the

, sameproportion as the increasein B. .This

is owing to the fact thatthe. change in the total-resistance of thefield circuitisvery small. As aresultthe voltage ,acrossithe contacts 10 and 11 increasesandcausesan increased current to 1 flow, in the winding 8. When the voltage across the above contacts has reached a certain value, theampere-turns of the coil 8 will be suflicient. to-causean .up-

ward movement of the core 6 carrying the contacts 1 and 5, this movement varying the resistance step by step. Immediately the first step has been traversed the trembler relay will alter the ratio V Qdurationeofbreak' and consequently the voltage of the dynamo 1 with the result that the ampere-turns of the coil. 8. are again reduced. .If the voltage at the terminals of the dynamofalls, the sequence ,o-foperations takesplacein the reverse order. In order to prevent the core 6 beingmovedwith every trifling variation oi the voltage. between the contactslOand'H, I and to arrange for step by step regulation the regulating contacts 4 was are madeiwide enough to bridge thegaps betweena series of contacts which form. tapping points on the resistance .3 in the well-known manner.

- Qtherknown means may. be. employed for producing this .step-by-step variation.

The chietadvantage of. the, arrangement described above is thatithe, finev regulation is i performed through themedium ota'treinbler relay which gives. very closeregulation. The a coil. 7 shown in. .the figure is. not. an essential feature 0f:the inventionand may be dissistance 20.which is provided with adjustable contacts similar; to those used for the resist- .ance Binlhgure 1 .aforedescribed. These contacts are carrled on-a core 19. arranged in movable relationship with. the co'il 30 which isenergized with..direct-current from the exciter. circuit. "Thearrangem'ent, shown in Figure2 difiers. chiefly-from that of Figure ,1-in theprovision of aspecial, relaywhich controls the trembling action of the contacts 22 and 23. The coil 27 is connected to two of thealternator terminals and is provided with .a corev26,,.its. function being to vibrate the [diaplu'agm25 carrying the contact 24. The naturalffrequency of this diaphragm is approximately equal to that of the alternating current with which the coil '27 is energized vandthe contact .24 will therefore execute a vibration of definite frequency and with a.

certain amplitude. The contact 23 is flexibly connected to, the core 21' by a'spring 22, and

vwill therefore commence to follow the motion oi the contact 24. As soon as the voltage at c the, .alternaton terminals exceeds the normal .or. ratedval-ue the core, 21 is drawn upwards 'by the coil128, thus momentarily separating the contacts 23 and .24. 'The -momentary separation of these contacts inserts the section lying between thecontacts on the resistance 20 into the field circuit of the exciter. This results in a variation of the ratio duration of. short-circuit duration of break as with the arrangement in Figure 1, the ratio being increased or decreased according to the direction of the voltage change. Under normal voltage conditions the core 21 is held in equilibrium by the coil 28,- and is raised or lowered according to the change in the voltage.

The method of regulation described above is not limited to voltage but may be extended to current, power, and power factor regulation. The regulator may be given a compound characteristic and means for compensating disturbing influences may be provided. The connection between the regulator and generator may be made through potential and current transformers if the conditions require this.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1. A vibrating contact regulator for electrical machines and systems comprising a regulable resistance, a main and an auxiliary contact at a fixed distance apart but slidably adjustable on said regulable resistance, said contacts being adapted to be operated in concert at a fixed distance apart, and spanning part of said regulable resistance and a pair of vibrating contacts controlled by the quantity it is desired to regulate, connected one to said main and the other to said auxiliary contact.

2. A vibrating contact regulator for electrical machines and systems comprising, in combination, a step-by-step resistance for performing the required regulation, main and auxiliary contacts operating at a fixed distance apart in adjustable relation with said resistance, a pair of vibrating contacts connected respectively to the said main and auxiliary contacts, means responsive to the quantity to be regulated for effecting the vibration of said vibrating contacts and means responsive to the voltage existing between said vibrating contacts for adjusting the position of the aforesaid main and auxiliary contacts relative to the step-by-step resistance.

3. A vibrating cont-act regulator for voltage regulation of direct-current machines comprising in combination, a step-by-step resistance controlling the field current of the machine, main and auxiliary contacts operating at a fixed distance apart in adjust-able relation with said resistance, a pair of vibrating contacts connected respectively to said main and auxiliary contacts, means responsive to the voltage of the machine for effecting the vibration of said vibrating contacts and means responsive to the voltage existing between said vibrating contacts for adjusting the position of the aforesaid main and auxiliary contacts relative to the step-by-step re sistance.

4. A vibrating contact regulator for directcurrent machines and systems comprising, in combination, a step-by-step resistance adaptcd to control the field of the machine, main and auxiliary contacts operating at a fixed distance apart in adjustable relationship with said resistance, a pair of vibrating contacts connected respectively to the said main and auxiliary contacts, means responsive to the quantity to be regulated for effecting the vibration of said vibrating contacts, a winding adapted to influence the action of said Vibrating contacts connected between the aforesaid main and auxiliary contacts, and means responsive to the voltage existing between said vibrating contacts for adjusting the position of the said main and auxiliary cont-acts relative to the step-by-step resistance.

In testimony whereof I have signed my name to this specification.

FRANQOIS MAURON. 

